Mine looks weird but it's decorated:

    @star
    @lights
    @balls
    def christmas_tree():
        n1 = Node()
        n2 = Node()
        n3 = Node()
        n4 = Node()
        n5 = Node()
        n6 = Node()
        n7 = Node()
        n8  = Node(n1, None)
        n9  = Node(n2, n3)
        n10 = Node(n4, n5)
        n11 = Node(n8, n9)
        n12 = Node(n6, n7)
        n13 = Node(None, n11)
        n14 = Node(None, n12)
        return Node(n13, n14)

    christmas_tree()